The present invention relates to 1,2,3-thiadiazole derivatives, plant disease controller containing said compounds as active ingredient thereof, and a method for using the same.
In JP-A-54-9272 are disclosed 1,2,3-thiadiazole-5-carboxylic acid derivatives, a method for producing said compounds, and compositions having herbicidal and plant growth regulating activities which contain said compounds. Further, in Canadian Patent No. 947297, JP-A-55-141476 and JP-A-56-108776, it is disclosed that benzoxazine derivatives are useful as herbicide.
The microorganisms and Eumycetes which are to be controlled with fungicides are characterized by rapidness of alteration of generations, and the problem of resistance to fungicides has long been discussed. Thus, it is desired to develop a novel fungicide having an excellent effect.
With the aim of developing a novel plant disease controller, the present inventors have continued elaborated studies to find that the 1,2,3-thiadiazole derivatives of the present invention represented by general formula (I) are useful as plant disease controller. Based on this finding, the present invention has been accomplished.
As typical compounds of the present invention, the 1,2,3-thiadiazole compounds represented by the following general formulas (I-a) and (I-b) can be referred to: 
wherein R1, R3, R4, n, X and Y are as defined later, 
wherein R1, R5, R6 and m are as defined later.
That is, the present invention relates to 1,2,3-thiadiazole derivatives represented by the following general formula (I), a plant disease controller containing said compounds as active ingredient thereof, and a method for using the same: 
[wherein R1 represents hydrogen atom, halogen atom, (C1-C6) alkyl group, halo (C1-C6) alkyl group, hydroxy (C1-C6) alkyl group, (C1-C6) alkoxy (C1-C6) alkyl group, (C3-C6) cycloalkyl group, (C1-C6) alkoxycarbonyl (C1-C6) alkyl group, (C1-C6) alkylcarbonyl (C1-C6) alkyl group, (C1-C6) alkylcarbonyloxy (C1-C6) alkyl group, phenyl group, substituted phenyl group having 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group and halo (C1-C6) alkoxy group, phenyl (C1-C6) alkyl group, substituted phenyl (C1-C6) alkyl group having, on the ring thereof, 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group and halo (C1-C6) alkoxy group, phenoxy (C1-C6) alkyl group, substituted phenoxy (C1-C6) alkyl group having, on the ring thereof, 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group and halo (C1-C6) alkoxy group, phenylcarbonyloxy (C1-C6) alkyl group, substituted phenylcarbonyloxy (C1-C6) alkyl group having, on the ring thereof, 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group and halo (C1-C6) alkoxy group or (C1-C6) alkoxycarbonyl group; and
R2 represents the following formula (A): 
xe2x80x83(wherein R3, which may be same or different, represents halogen atom, cyano group, nitro group, hydroxyl group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group or carboxyl group, n represents an integer of 0 to 3, and R4 represents hydrogen atom, halogen atom, cyano group, nitro group, hydroxyl group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group or carboxyl group, further, R3 or R3 and R4 may be taken conjointly with a carbon atom of the adjacent phenyl group to form a (C1-C6) alkenylene ring, and X and Y may be same or different and represent oxygen atom or sulfur atom); or
the following formula (B): 
xe2x80x83(wherein R5 represents hydrogen atom, (C1-C20) alkyl group, halo (C1-C20) alkyl group, (C2-C20) alkenyl group, halo (C2-C20) alkenyl group, (C2-C20) alkynyl group, halo (C2-C20) alkynyl group, (C3-C7) cycloalkyl group, (C3-C7) cycloalkenyl group, (C1-C6) alkoxy (C1-C6) alkyl group, phenyl group, substituted phenyl group having 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group, hydroxyl group, carboxyl group, (C1-C6) alkoxycarbonyl group, carbamoyl group and aminocarbonyl group substituted with same or different hydrogen atoms or (C1-C6) alkyl groups, phenyl (C1-C6) alkyl group, substituted phenyl (C1-C6) alkyl group having, on the ring thereof, 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group and hydroxyl group, or a 5- or 6-membered heterocyclic group having at least one, same or different hetero atoms selected from the group consisting of oxygen atom, sulfur atom and nitrogen atom, further, said heterocyclic group may have, on the ring thereof, at least one, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group and hydroxyl group;
R6 represents (C1-C20) alkyl group, halo (C1-C20) alkyl group, (C2-C20) alkenyl group, halo (C2-C20) alkenyl group, (C2-C20) alkynyl group, halo (C2-C20) alkynyl group, (C3-C7) cycloalkyl group, (C3-C7) cycloalkenyl group, (C1-C6) alkoxy (C1-C6) alkyl group, phenyl group, substituted phenyl group having 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group and hydroxyl group, phenyl (C1-C6) alkyl group, substituted phenyl (C1-C6) alkyl group having, on the ring thereof, 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group and hydroxyl group, a 5- or 6-membered heterocyclic group having at least one, same or different hetero atoms selected from the group consisting of oxygen atom, sulfur atom and nitrogen atom, further, said heterocyclic group may have, on the ring thereof, at least one, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group and hydroxyl group, or
xe2x80x94N(R7)R8
xe2x80x83(wherein R7 and R8, which may be same or different, represent (C1-C20) alkyl group, halo (C1-C20) alkyl group, cyano (C1-C6) alkyl group, (C2-C20) alkenyl group, halo (C2-C20) alkenyl group, (C2-C20) alkynyl group, halo (C2-C20) alkynyl group, (C3-C7) cycloalkyl group, (C3-C7) cycloalkenyl group, (C1-C6) alkoxy (C1-C6) alkyl group, (C1-C6) alkoxy (C1-C6) alkoxy (C1-C6) alkyl group, (C1-C12) alkylcarbonyl group, halo (C1-C12) alkylcarbonyl group, (C1-C12) alkoxycarbonyl group, (C1-C12) alkoxycarbonyl (C1-C6) alkyl group, (C3-C7) cycloalkylcarbonyl group, substituted (C3-C7) cycloalkylcarbonyl group substituted with at least one, same or different halogen atoms, (C2-C12) alkenyloxycarbonyl group, (C2-C12) alkenyloxycarbonyl (C1-C6) alkyl group, (C2-C12) alkynyloxycarbonyl group, (C2-C12) alkynyloxycarbonyl (C1-C6) alkyl group, (C1-C6) alkoxy (C1-C6) alkoxycarbonyl group, (C1-C6) alkoxy (C1-C6) alkoxycarbonyl (C1-C6) alkyl group, di(C1-C12) alkylaminocarbonyl group in which (C1-C12) alkyl groups may be same or different, di(C1-C12) alkylaminocarbonyl (C1-C6) alkyl group in which (C1-C12) alkyl groups may be same or different, phenyl group, substituted phenyl group having 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group, hydroxyl group, carboxyl group, (C1-C6) alkoxycarbonyl group, carbamoyl group and aminocarbonyl group substituted with same or different hydrogen atoms or (C1-C6) alkyl groups, phenyl (C1-C6) alkyl group, substituted phenyl (C1-C6) alkyl group having, on the ring thereof, 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group and hydroxyl group, phenylcarbonyl group, substituted phenylcarbonyl group having, on the ring thereof, 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group and hydroxyl group, phenoxycarbonyl group, substituted phenoxycarbonyl group having, on the ring thereof, 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group and hydroxyl group, phenyl (C1-C6) alkoxycarbonyl group, substituted phenyl (C1-C6) alkoxycarbonyl group having, on the ring thereof, 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group and hydroxyl group, phenyl (C1-C6) alkoxycarbonyl (C1-C6) alkyl group, substituted phenyl (C1-C6) alkoxycarbonyl (C1-C6) alkyl group having, on the ring thereof, 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group and hydroxyl group, a 5- or 6-membered heterocyclic group having at least one, same or different hetero atoms selected from the group consisting of oxygen atom, sulfur atom and nitrogen atom, further, said heterocyclic group may have, on the ring thereof, at least one, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group and hydroxyl group, or a 5- or 6-membered heterocyclic carbonyl group having at least one, same or different hetero atoms selected from the group consisting of oxygen atom, sulfur atom and nitrogen atom, further, said heterocyclic ring may have, on the ring thereof, at least one, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group and hydroxyl group, and
alternatively, R7 and R8 may be taken conjointly to form a (C2-C6) alkylene group which may be intercepted by oxygen atom, sulfur atom or xe2x80x94Nxe2x80x94R9 (in which R9 represents hydrogen atom, (C1-C6) alkyl group, (C1-C6) alkylcarbonyl group, halo (C1-C6) alkylcarbonyl group, (C1-C6) alkoxycarbonyl group, phenyl group, phenyl (C1-C6) alkyl group or phenyl carbonyl group), further, said alkylene group may be substituted with at least one, same or different substituents selected from the group consisting of (C1-C6) alkyl group, halo (C1-C6) alkyl group, phenyl group, phenyl (C1-C6) alkyl group, oxo group and thioxo group); and m represents an integer of 0 to 2)].
Definition of the general formula (I) representing the 1,2,3-thiadiazole derivatives of the present invention will be explained below, in which xe2x80x9cn-xe2x80x9d means normal, xe2x80x9ci-xe2x80x9d means iso, xe2x80x9cs-xe2x80x9d means secondary and xe2x80x9ct-xe2x80x9d means tertiary. In the definition of general formula (I), the term xe2x80x9chalogen atomxe2x80x9d means chlorine atom, bromine atom, iodine atom or fluorine atom; and the term xe2x80x9c(C1-C20) alkyl groupxe2x80x9d means a straight or branched chain alkyl group having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, n-pentyl, neopentyl, n-hexyl, octyl, decyl, hexadecanyl, octadecanyl, eicosanyl and the like.
The term xe2x80x9chalo (C1-C20) alkyl groupxe2x80x9d means a straight or branched chain alkyl group having 1 to 20 carbon atoms which may be substituted with at least one, same or different halogen atoms. Examples thereof include chloromethyl, difluoromethyl, trifluoromethyl, bromomethyl, 2-bromoethyl, 1,2-dichloropropyl, 2,2,3,3,3-pentafluoropropyl, 2,3-dibromobutyl, 4-iodobutyl, chlorohexyl, bromodecenyl, iodohexadecanyl, fluoroeicosanyl and the like.
The term xe2x80x9chydroxy (C1-C6) alkyl groupxe2x80x9d include a straight or branched chain alkyl group having 1 to 6 carbon atoms substituted with at least one hydroxyl groups. Examples thereof include hydroxymethyl, 1,2-dihydroxypropyl and the like. The term xe2x80x9c(C1-C6) alkoxy groupxe2x80x9d means a straight or branched chain alkoxy group having 1 to 6 carbon atoms. Examples thereof include methoxy, ethoxy, i-propoxy and the like. The term xe2x80x9c(C1-C6) alkoxy (C1-C6) alkyl groupxe2x80x9d means a straight or branched chain alkyl group having 1 to 6 carbon atoms substituted with at least one alkoxy groups having 1 to 6 carbon atoms.
The term xe2x80x9c(C3-C6) cycloalkyl groupxe2x80x9d means a cyclic alkyl group having 3 to 6 carbon atoms, of which examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like.
The term xe2x80x9c(C1-C6) alkoxy groupxe2x80x9d means a straight or branched chain alkoxy group having 1 to 6 carbon atoms, of which examples methoxy, ethoxy, i-propoxy and the like.
The term xe2x80x9chalo (C1-C6) alkoxy groupxe2x80x9d means a straight or branched chain alkoxy group having 1 to 6 carbon atoms which may be substituted with at least one, same or different halogen atoms. Examples thereof include trifluoromethoxy, 2-chloroethoxy, 4-bromoethoxy, 4-iodohexyloxy and the like.
The term xe2x80x9c(C2-C20) alkenyl groupxe2x80x9d means a straight or branched chain alkenyl group having at least one double bonds and 2 to 20 carbon atoms. Examples thereof include vinyl, allyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, pentenyl, hexenyl, hexadecenyl, octadecenyl, eicosenyl and the like. The term xe2x80x9chalo (C2-C20) alkenyl groupxe2x80x9d means a straight or branched chain alkenyl group having 2 to 20 carbon atoms, wherein at least one of the hydrogen atoms thereof are substituted with same or different halogen atoms. Examples thereof include 2-chloro-2-propenyl, 2,3-dibromo-2-propenyl, 3,3-dichloro-2-propenyl and the like.
The term xe2x80x9c(C2-C20) alkynyl groupxe2x80x9d means a straight or branched chain alkynyl group having at least one triple bonds and 2 to 20 carbon atoms. Examples thereof include ethynyl, 2-propynyl, 1-methyl-2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, hexadec-8-ynyl and the like. The term xe2x80x9chalo (C2-C20) alkynyl groupxe2x80x9d means a straight or branched chain alkynyl group having 2 to 20 carbon atoms, wherein at least one of the hydrogen atoms thereof are substituted with same or different halogen atoms. Examples thereof include 2-chloroethynyl, 1-bromo-2-propynyl, 3-iodo-2-propynyl and the like.
The term xe2x80x9c(C1-C6) alkoxy (C1-C6) alkyl groupxe2x80x9d means a straight or branched chain alkyl group having 1 to 6 carbon atoms, wherein at least one of the hydrogen atoms thereof are substituted with straight or branched chain alkoxy groups having 1 to 6 carbon atoms. Examples thereof include methoxymethyl, ethoxymethyl, 1-methoxypropyl, 6-methoxyhexyl, 2,3-dimethoxypropyl, 3-methoxy-4-propoxybutyl, 3-(1,2-dimethylpropoxy)-2-methylpropyl and the like. The term xe2x80x9chalo (C1-C6) alkoxy (C1-C6) alkyl groupxe2x80x9d means an (C1-C6) alkoxy (C1-C6) alkyl group, wherein at least one the hydrogen atoms thereof are substituted with halogen atoms.
The term xe2x80x9c5- or 6-membered heterocyclic group having at least one, same or different hetero atoms selected from the group consisting of oxygen atom, sulfur atom and nitrogen atomxe2x80x9d means a saturated or unsaturated, 5- or 6-membered heterocyclic group. As examples thereof, mention can be made of the substituents derived from heterocyclic ring such as furan, thiophene, pyran, pyrrole, imidazole, pyrazole, isothiazole, isoxazole, pyridine, pyrazine, pyrimidine, pyridazine, 1,2,3-thiadiazole, 1,3,4-thiadiazole, 1,2,4-triazole, 1,2,4-triazine, 1,3,5-triazine, dioxane, dithiolan, 1,3-thiazine, piperidine, piperazine, morpholine and the like.
In the present invention, the following compounds are preferable:
On R1, preferable substituents are (C1-C6) alkyl groups, and particularly preferable substituents are (C1-C3) alkyl groups.
In cases where R2 is represented by the formula (A), preferable substituents are those in which n is zero and R4 is hydrogen atom or halogen atom. In cases where R2 is represented by the formula (B), preferable substituents are those in which R5 is hydrogen atom and R6 is a phenyl group or a substituted phenyl group having 1 to 5, same or different substituents selected from the group consisting of halogen atom, cyano group, nitro group, (C1-C6) alkyl group, halo (C1-C6) alkyl group, (C1-C6) alkoxy group, halo (C1-C6) alkoxy group, hydroxyl group, carboxyl group, (C1-C6) alkoxycarbonyl group, carbamoyl group and aminocarbonyl group substituted with same or different hydrogen atoms or (C1-C6) alkyl group, or xe2x80x94N(R7)R8 (in which R7 and R8 may be same or different and represent (C1-C6) alkyl group, (C1-C6) alkoxycarbonyl (C1-C6) alkyl group or (C1-C6) alkoxycarbonyl group or R7 and R8, taken conjointly, form a (C2-C6) alkylene group which may be intercepted by oxygen atom, sulfur atom or xe2x80x94NR9 (in which R9 represents hydrogen atom, (C1-C6) alkyl group, phenyl group, phenyl (C1-C6) alkyl group or phenyl carbonyl group), further, said alkylene group may be substituted with at least one, same or different substituents selected from the group consisting of (C1-C6) alkyl group, phenyl group, phenyl (C1-C6) alkyl group, oxo group and thioxo group).
In the general formula (I) of the present invention, the 1,2,3-thiadiazole derivatives represented by the general formula (I-a) can be produced according to the production process 1 and 2 mentioned below, or the like. Production Process 1: In the case where R2 represents formula (A) and X and Y are oxygen atoms 
wherein R1, R3, R4 and n are as defined above and Hal represents a halogen atom.
The 1,2,3-thiadiazole derivative represented by general formula (I-a-1) can be produced by reacting a 1,2,3-thiadiazole compound represented by general formula (II) with an anthranilic acid compound represented by general formula (III) in the presence of an inert solvent and a base to form a compound represented by general formula (IV), isolating the compound (IV), and then reacting the compound (IV) with an acid anhydride.
Alternatively, it is also possible to produce the compound represented by general formula (I-a-1) directly by reacting a 1,2,3-thiadiazole compound represented by general formula (II) with an anthranilic acid compound represented by general formula (III) in the presence of an inert solvent and a base.
1-1. General Formula (II)xe2x86x92General Formula (IV)
The inert solvent used in this reaction may be any inert solvent so far as it does not obstruct the progress of this reaction markedly. Examples of the inert solvent include alcohols such as methanol, ethanol, propanol, butanol and the like; aromatic hydrocarbons such as benzene, toluene, xylene and the like; halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride, chlorobenzene and the like; esters such as ethyl acetate and the like; nitriles such as acetonitrile, benzonitrile and the like; acyclic ethers such as methyl cellosolve, diethyl ether and the like; cyclic ethers such as dioxane, tetrahydrofuran and the like; sulfolane, dimethyl sulfone, dimethyl sulfoxide, water, and the like. These inert solvents can be used either alone or in the form of a mixture of two or more.
As said base used in this reaction, inorganic bases and organic bases can be referred to. The inorganic bases include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and the like, alkali metal carbonates, and the like. The organic bases include tertiary amines such as triethylamine and the like, and pyridines. These bases can be used in an amount appropriately selected in the range of from equimolar to excessive molar quantities to the 1,2,3-thiadiazole represented by general formula (II).
The reaction temperature may be a temperature falling in the range of from room temperature to the boiling point of the inert solvent used. Although the reaction time varies with the scale of reaction and the reaction temperature, it is from several minutes to 48 hours.
After completion of the reaction, the compound represented by general formula (IV) is isolated from the reaction system containing the objective product, and a purification may be practiced, if desired. Alternatively, the reaction mixture may directly be used in the subsequent step of the reaction without isolating the compound of general formula (IV).
The compound represented by general formula (II) can be produced according to the method described in JP-A-8-325110.
1-2. General Formula (IV)xe2x86x92General formula (I-a-1)
This reaction is a cyclization reaction. If the reactant (acid anhydride) is used in an excessive amount, the acid anhydride can be made to serve not only as a reactant but also as an inert solvent.
The reaction temperature may be in the range of from room temperature to the boiling point of the inert solvent used. It is preferable to carry out the reaction in the boiling temperature zone of the inert solvent used.
Although the reaction time may vary with scale and temperature of the reaction, it is from several minutes to 48 hours.
After completion of the reaction, the 1,2,3-thiadiazole derivative represented by general formula (I-a-1) is isolated from the reaction system containing the objective product in the conventional manner. If desired, a purification may be carried out.
1-3. General Formula (II)xe2x86x92General Formula (I-a-1)
According to this reaction, the 1,2,3-thiadiazole derivative represented by general formula (I-a-1) can be produced in the same manner as in Reaction 1-1. A direct production can be practiced by prolonging the reaction time.
Production Process 2: In the case where R2 represents formula (A) and X and Y are sulfur atoms 
wherein R1, R3, R4 and n are as defined above.
A 1,2,3-benzothiadiazole derivative represented by general formula (I-a-2) can be produced by reacting a 1,2,3-thiadiazole derivative represented by general formula (I-a-1) with a sulfurizing agent such as Lauesson""s reagent, P4S10 or the like in the presence of an inert solvent.
The inert solvent which can be used in this reaction is the same as those used in the Production Process 1-1.
The amount of the sufurizing agent such as Lauesson""s reagent, P4S10 or the like may be appropriately selected in the range of from an equimolar quantity to the 1,2,3-thiadiazole derivative of general formula (I-a-1) to a largely excessive quantity. Preferably, the sulfurizing agent is used in a largely excessive quantity.
The reaction temperature is in the range from room temperature to the boiling temperature zone of the inert solvent used. Although the reaction time may vary with scale and temperature of the reaction, it is from several minutes to 48 hours.
After completion of the reaction, the compound represented by general formula (I-a-2) is isolated from the reaction system containing the objective product in the usual manner. If desired, a purification may be carried out.
This production method can be put into practice according to the description of Heterocycles, 19, 2093 (1882), etc.
Among the compounds represented by general formula (I) of the present invention, the 1,2,3-thiadiazole derivatives represented by general formula (I-b) can be produced, for example, by the production methods exemplified below.
Production Process 3: In the case where R2 represents formula (B) 
wherein R1, R5, R6 and m are as defined above and X represents a leaving group.
A 1,2,3-thiadiazole derivative represented by general formula (I-b-1) can be produced by reacting a compound represented by general formula (IIxe2x80x2) with a compound represented by general formula (V) in the presence of an inert solvent and a base.
The solvent used in this reaction may be any solvents, so far as they do not disturb the progress of the reaction. Examples of the solvent include alcohols such as methanol, ethanol, propanol, butanol and the like, aromatic hydrocarbons such as benzene, toluene, xylene and the like, halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride, chlorobenzene and the like, esters such as ethyl acetate and the like, nitrites such as acetonitrile, benzonitrile and the like, acyclic ethers such as methyl cellosolve, diethyl ether and the like, cyclic ethers such as dioxane, tetrahydrofuran and the like, sulfolane, dimethyl sulfone, dimethyl sulfoxide, water, and the like. These inert solvents may be used either alone or in the form of a mixture of two or more.
As the base, inorganic and organic bases can be used. The inorganic bases include alkali hydroxides such as sodium hydroxide, potassium hydroxide and the like and alkali carbonates; and the organic bases include tertiary amines such as triethylamine and the like, pyridines and the like. These bases are used in an appropriate amount falling in the range of from an equimolar quantity to the 1,2,3-thiadiazole compound represented by general formula (IIxe2x80x2) to an excessive molar quantity.
Since this reaction is an equimolar reaction, the compound of formula (IIxe2x80x2) and the compound of formula (V) may be used in equimolar quantities. It is also possible, however, to used any one of the reactants in an excessive quantity.
The reaction temperature is in the range of from room temperature to the boiling temperature zone of the inert solvent. Although the reaction time may vary with scale and temperature of the reaction, it is from several minutes to 48 hours.
After completion of the reaction, the 1,2,3-thiadiazole derivative represented by general formula (I-b-1) is isolated from the reaction system containing the objective product in the usual manner. If desired, a purification may be carried out.
Production Process 4: In the case where R2 represents formula (B) 
wherein R1, R5, R6 and m are as defined above and Hal represents halogen atom.
A 1,2,3-thiadiazole derivative represented by general formula (I-b-1) can be produced by reacting a compound represented by general formula (VI) with a compound represented by general formula (VII) in the presence of an inert solvent and a base.
This reaction can be carried out according to the description of xe2x80x9cShin Jikken Kagaku Kozaxe2x80x9d, 14-III, Page 1803 (published by Maruzen K. K.), etc. Production Process 5: In the case where R2 represents formula (B) and R6 represents xe2x80x94N(R7)R8 
5-1. 
wherein R1, R5, R7, R8 and Hal are as defined above.
A 1,2,3-thiadiazole derivative represented by general formula (I-b-2) can be produced by halosulfenylating an amine represented by general formula (VIII) with sulfur monochloride, sulfur dichloride or the like to obtain a compound represented by general formula (IX), followed by reacting the thus formed compound (IX) with a compound represented by general formula (VI) in the presence of a base and an inert solvent.
5-2. 
wherein R1, R5, R7, R8 and Hal are as defined above.
A 1,2,3-thiadiazole derivative represented by general formula (I-b-2) can be produced by treating a compound represented by general formula (VI) in the same manner as in 5-1 to obtain a compound represented by general formula (X), isolating or not isolating the thus formed compound (X), and then reacting the compound (X) with an amine represented by general formula (VIII) in the presence of a base and an inert solvent.
The reactions of 5-1 and 5-2 can be carried out according to the procedure disclosed in JP-A-58-26804, etc.
The compounds represented by general formula (IIxe2x80x2) and general formula (VI) can be produced according to the procedure described in JP-A-8-325110, etc.
Next, typical examples of the 1,2,3-thiadiazole derivatives represented by general formula (I) are shown below. The invention is by no means limited by these compounds. In Table 1 are shown the compounds represented by general formula (I-a). In Table 2 are shown the compounds represented by general formula (I-b).
General formula (I-a)
In Table 1, xe2x80x9cc-xe2x80x9d represents an alicyclic monocyclic hydrocarbon group, and xe2x80x9cPhxe2x80x9d represents a phenyl group. In some of the compounds, the property was pasty. Nuclear magnetic resonance data of these compounds are shown below.
In the table, TMS means tetramethylsilane.
Next, typical examples of the 1,2,3-thiadiazole derivatives represented by general formula (I-b) are shown below. The present invention is by no means limited by these compounds.
General formula (I-b)
In Table 2, xe2x80x9cPhxe2x80x9d represents a phenyl group, xe2x80x9cc-xe2x80x9d represents an alicyclic hydrocarbon group, and Q1, Q2, Q3 and Q4 represent the following substituents: 
The 1,2,3-thiadiazole derivatives represented by general formula (I) are useful as a plant disease controller, and they exhibit a very high controlling effect against various diseases. Specific examples of the diseases against which the compounds of the present invention exhibit a marked effect include rice blast (Pyricularia oryzae), rice sheath blight (Rhizoctonia solani), rice helminthosporium leaf spot (Cochiobolus miyabeanus), powdery mildew of various host plants such as powdery mildew of barley and wheat (Erysiphe graminis), oats crown rust (Puccinia coronata), stem rust of other plants, late blight of tomato (Phytophthora infestans), late blight of other plants, late blight or Phytophthora rots of various plants such as cucumber downy mildew (Pseudoperonospora cubensis), grape downy mildew (Plasmopara viticola), etc., apple scab (Venturia inaequalis), apple alternaria leaf spot (Alternaria mali), pear black spot (Alternaria kikuchiana), citrus melanose (Diaporthe citri), bacterial diseases due to Genus Pseudomonas such as cucumber bacterial blight (Pseudomonas syringae pv. lachrymans) and tomato bacterial wilt (Pseudomonas solanacearum), bacterial diseases due to Genus Xanthomonas such as cabbage black rot (Xanthomonas campestris), rice bacterial leaf blight (Xanthomonas oryzae) and citrus canker (Xanthomonas citri), and bacterial diseases due to Genus Erwinia such as cabbage bacterial soft rot (Erwinia carotovora), and viral diseases such as tobacco mosaic (tobacco mosaic virus), etc.
The plant disease controller of the present invention containing the 1,2,3-thiadiazole derivative represented by general formula (I) as an active ingredient exhibits a marked controlling effect against the above-mentioned diseases injuring the crop plants of paddy field, crop plants of upland field, fruit plants, vegetables, and other crop plants and flower plants. Therefore, the desired effects of the agrohorticultural disease controller of the present invention can be obtained by applying the disease controller to paddy field water, stalks and leaves or soil of the paddy field, upland field, fruit trees, vegetables, other crops, flowers and ornamental plants at a season at which the diseases are expected to occur, before their occurrence or at the time when their occurrence is confirmed.
In general, the plant disease controller of the present invention is used after being prepared into a conventionally usable form according to an ordinary manner for preparation of agrochemicals.
That is, the 1,2,3-thiadiazole derivative of the present invention represented by general formula (I) and, optionally, an adjuvant are blended with a suitable inert carrier in a proper proportion and prepared into a suitable preparation form such as suspension, emulsion, solution, wettable powder, granule, dust, tablet or the like through dissolution, separation, dispersion, mixing, impregnation, adsorption or adhesion.
The inert carrier used in the present invention may be either solid or liquid. As the solid carrier material, there can be referred to soybean flour, cereal flour, wood flour, bark flour, saw dust, powdered tobacco stalks, powdered walnut shells, bran, powdered cellulose, extraction residue of vegetables, powdered synthetic polymers or resins, clays (e.g. kaolin, bentonite, acid clay, etc.), talcs (e.g. talc, pyrophyllite, etc.), silica materials (e.g. diatomaceous earth, silica sand, mica, white carbon, i.e. synthetic high-dispersion silicic acid, also called finely divided hydrated silica or hydrated silicic acid, some of the commercially available products thereof contain calcium silicate as the major component), activated carbon, powdered sulfur, pumice, calcined diatomaceous earth, ground brick, fly ash, sand, calcium carbonate powder, calcium phosphate powder and other inorganic or mineral powders, chemical fertilizers (e.g. ammonium sulfate, ammonium phosphate, ammonium nitrate, urea, ammonium chloride, etc.), and compost. These solid carriers may be used alone or as a mixture thereof.
The liquid carrier material is selected from those which have solubility in themselves or those which have no solubility in themselves but are capable of dispersing an active ingredient by the aid of an adjuvant. The following are typical examples of the liquid carrier, which can be used alone or as a mixture thereof. Water; alcohols such as methanol, ethanol, isopropanol, butanol, ethylene glycol and the like; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone and the like; ethers such as ethyl ether, dioxane, cellosolve, dipropyl ether, tetrahydrofuran and the like; aliphatic hydrocarbons such as kerosene, mineral oils and the like, aromatic hydrocarbons such as benzene, toluene, xylene, solvent naphtha, alkylnaphthalene and the like; halogenated hydrocarbons such as dichlorethane, chloroform, carbon tetrachloride, chlorobenzenes and the like; esters such as ethyl acetate, diisopropyl phthalate, dibutyl phthalate, dioctyl phthalate and the like; amides such as dimethylformamide, diethylformamide, dimethylacetamide and the like; nitriles such as acetonitrile and the like; dimethyl sulfoxide; etc.
The following are typical examples of other adjuvants, which are used depending on purpose and may be used alone or in combination in some cases or not used at all.
For the purpose of emulsifying, dispersing, solubilizing and/or wetting an active ingredient, a surfactant is used. As the surfactant, there can be exemplified polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, polyoxyethylene higher fatty acid esters, polyoxyethylene resinates, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monooleate, alkylarylsulfonates, naphthalenesulfonic acid condensates, ligninsulfonates, higher alcohol sulfuric ester salts, etc.
Further, for the purpose of stabilizing, tackifying and/or binding a dispersion of an active ingredient, there may be used an adjuvant such as casein, gelatin, starch, methyl cellulose, carboxymethyl cellulose, gum arabic, polyvinyl alcohol, turpentine oil, bran oil, bentonite, ligninsulfonate and the like.
For the purpose of improving flowability of a solid product, adjuvants such as wax, stearic acid salts, alkyl esters of phosphoric acid, etc.
Adjuvants such as naphthalenesulfonic acid condensates, polycondensates of phosphates, etc. may be used as a peptizer for dispersible products.
Adjuvants such as silicon oils may also be used as a defoaming agent.
The content of active ingredient may be varied in accordance with need. For example, in dusts and granules, the suitable content thereof is from 0.01 to 50% by weight. In emulsifiable concentrate and wettable powder, too, an active ingredient content of from 0.01 to 50% by weight is suitable.
The plant disease controller of the present invention is used to control various diseases by applying its effective amount for the disease control either as it is or in the form of dilution or suspension in an appropriate quantity of water or the like, to a crop on which occurrence of the diseases is expected or to a site where the occurrence of the diseases is undesirable. For example, in order to control the diseases of paddy rice, said disease controller can be used by the method of submerged application to a regular paddy field, application to a rice nursery bed, dressing of seeds for direct sowing on flooded paddy field, or seed disinfection. For the purpose of controlling the diseases of wheat and barley, the plant disease controller of the present invention may be sprayed to stalks or leaves, or applied to the soil aiming at absorption from the roots.
The applying dosage of the plant disease controller of the present invention may vary depending on various factors such as purpose, disease to be controlled, growth state of crop, tendency of occurrence of the disease, weather, environmental conditions, preparation form, method of application, site of application, and time of application. However, it may be properly chosen in the range of 0.1 gram to 10 kilograms, in terms of active ingredient, per 10 areas depending upon purposes.
It is also possible to use the plant disease controller of the present invention in admixture with other plant disease controllers in order to expand spectrum of controllable diseases and the period of time when an effective application is possible, or to reduce the dosage.